How much was the boost gauge fluctuating by, and how fast (flicking up and down quickly)? My pump rebuilder asked me to see if mine was fluctuating, but I couldn’t see it doing this on my Redarc gauge.
electric fuel pump assist? (1 Viewer)
- Thread starter coldtaco
- Start date
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- Thread starter
- #22
It was probably fluctuating around 2psi, I would say it would move pretty fast but hold the new psi for a second or two before returning back to normal, but like you said it is hard to get a good look at it while driving.
Frustrating!!!
Maybe try a small jerry can connected straight to the lift pump (probably what I will try next) - just to totally eliminate anything up to the lift pump… probably my next move….
Nz Nath
SILVER Star
I already mentioned it, but a cheapo oil pressure guage will work for fuel pressure as well. I think mine was from supercheapauto, had the right adapter to screw into the bleeder hole on the fuel filter housing, and the hose was long enough to run through an open window into the cab.
- Thread starter
- #26
I will see if I can get this setup and try that. I have noticed a fuel leak at fuel return union on the pump that I will try and fix, but I can’t see that causing any issues since it is after the pressure/injectors, unless it is allowing air in and then letting air back to the pump. I plumbed the return to a T in front of the lift pump, instead of back to the tank.
The leak you describe would absolutely cause issues.
- Thread starter
- #28
the gauge I got was way to high pressure so it was very hard to see any small changes. I might try again tomorrow. There was one thing that happened yesterday at about the same time that I noticed the boost pressure swing. The alternator had quit working, this morning I found a plug had come loose therefore turning off the alternator. Don't know if the plug was creating enough contact and then loosening enough to cause the alternator to come on/then go off due to the vibration?
Would this suit (up to 10psi)?
- Thread starter
- #30
Would definitely be better
Nz Nath
SILVER Star
Your feed pressure should be up around 20psi.
- Thread starter
- #32
Only shows maybe 3, 4psi at all modes, idle, acceleration, cruise at 55, 65mph. I’m guessing the gauge isn’t working right or I didn’t do something right
Nz Nath
SILVER Star
Or you’ve confirmed you have a fuel supply problem
Nz Nath
SILVER Star
See this thread regarding pressure for the 12ht 12HT pump body pressure - https://forum.ih8mud.com/threads/12ht-pump-body-pressure.534403/
Pressure is set by the valve in the return banjo bolt. There’s a ball, spring and adjusting shims. I added some extra shims and stretched my spring a bit on my 13bt, raising pressure from about 21psi to 25. If you had a leaky ball/seat or a broken spring that could cause low pressure.
Pressure is set by the valve in the return banjo bolt. There’s a ball, spring and adjusting shims. I added some extra shims and stretched my spring a bit on my 13bt, raising pressure from about 21psi to 25. If you had a leaky ball/seat or a broken spring that could cause low pressure.
